Field of the Invention
The present invention generally relates to a valve for use in the brake system of an automotive vehicle and more specifically to a proportioning valve located between the master cylinder and the wheel cylinders in a hydraulic braking system. The valve is constructed with a one-piece housing screw threaded directly into a port on the master cylinder and provided with an outlet port at the opposite end of the housing. The exterior of the housing includes a groove receiving an O-ring which overlies a radially extending vent passageway communicating with the interior chamber within the housing. A spring biased piston is positioned in the chamber together with a removable insert and poppet associated with a passage through the piston with these components retained in place by retaining ring structures, springs and the like and sealed by O-ring seals. The construction of the housing and piston enables increased expansion volume which provides for an increased pressure drop downstream of the valve when the pressure is released upstream of the valve. The one-piece housing and insert enables the housing to be machined from the poppet end thereby providing ease of manufacture, greater accuracy, ease of assembly and reduction in costs of machining time and materials.